<?php
class wechatAppPay{ 
			
			//接口API URL前缀
			const API_URL_PREFIX = 'https://api.mch.weixin.qq.com';

			//下单地址URL
			const UNIFIEDORDER_URL = "/pay/unifiedorder";

			//查询订单URL
			const ORDERQUERY_URL = "/pay/orderquery";

			//关闭订单URL
			const CLOSEORDER_URL = "/pay/closeorder";

			//公众账号ID
			private $appid;

			//商户号
			private $mch_id;

			//随机字符串
			private $nonce_str;

			//签名
			private $sign;

			//商品描述
			private $body;

			//商户订单号
			private $out_trade_no;

			//支付总金额
			private $total_fee;

			//终端IP
			private $spbill_create_ip;

			//支付结果回调通知地址
			private $notify_url;

			//交易类型
			private $trade_type;

			//支付密钥

			private $key;

			//证书路径
			private $SSLCERT_PATH;


			private $SSLKEY_PATH;

			//所有参数
			private $params = array();

			public function __construct($appid, $mch_id, $notify_url, $key)
			{
				$this->appid = $appid;
				$this->mch_id = $mch_id;
				$this->notify_url = $notify_url;
				$this->key = $key;
			}
			/**
			* 下单方法
			* @param $params 下单参数
			*/
			public function unifiedOrder( $params ){

			$this->body = $params['body'];

			$this->out_trade_no = $params['out_trade_no'];

			$this->total_fee = $params['total_fee'];

			$this->trade_type = $params['trade_type'];

			$this->nonce_str = $this->genRandomString();

			$this->spbill_create_ip = $_SERVER['REMOTE_ADDR'];

			$this->params['appid'] = $this->appid;

			$this->params['mch_id'] = $this->mch_id;

			$this->params['nonce_str'] = $this->nonce_str;

			$this->params['body'] = $this->body;

			$this->params['out_trade_no'] = $this->out_trade_no;

			$this->params['total_fee'] = $this->total_fee;

			$this->params['spbill_create_ip'] = $this->spbill_create_ip;

			$this->params['notify_url'] = $this->notify_url;

			$this->params['trade_type'] = $this->trade_type;
			//获取签名数据
			$this->sign = $this->MakeSign( $this->params );

			$this->params['sign'] = $this->sign;

			$xml = $this->data_to_xml($this->params);

			$response = $this->postXmlCurl($xml, self::API_URL_PREFIX.self::UNIFIEDORDER_URL);

			/*var_dump($response);*/

			if( !$response ){

				return false;
			}

			$result = $this->xml_to_data( $response );


			if( !empty($result['result_code']) && !empty($result['err_code']) ){

				$result['err_msg'] = $this->error_code( $result['err_code'] );

			}
				return $result;
			}
			/**
			* 查询订单信息
			* @param $out_trade_no 订单号
			* @return array
			*/
			public function orderQuery( $out_trade_no ){
				
				$this->params['appid'] = $this->appid;

				$this->params['mch_id'] = $this->mch_id;

				$this->params['nonce_str'] = $this->genRandomString();

				$this->params['out_trade_no'] = $out_trade_no;

				//获取签名数据
				$this->sign = $this->MakeSign( $this->params );

				$this->params['sign'] = $this->sign;

				$xml = $this->data_to_xml($this->params);

				$response = $this->postXmlCurl($xml, self::API_URL_PREFIX.self::ORDERQUERY_URL);

			if( !$response ){

				return false;
			}

			$result = $this->xml_to_data( $response );

			if( !empty($result['result_code']) && !empty($result['err_code']) ){

				$result['err_msg'] = $this->error_code( $result['err_code'] );
			}
				return $result;
			}
			/**
			* 关闭订单
			* @param $out_trade_no 订单号
			* @return array
			*/
			public function closeOrder( $out_trade_no ){

				$this->params['appid'] = $this->appid;

				$this->params['mch_id'] = $this->mch_id;

				$this->params['nonce_str'] = $this->genRandomString();

				$this->params['out_trade_no'] = $out_trade_no;

				//获取签名数据
				$this->sign = $this->MakeSign( $this->params );

				$this->params['sign'] = $this->sign;

				$xml = $this->data_to_xml($this->params);

				$response = $this->postXmlCurl($xml, self::API_URL_PREFIX.self::CLOSEORDER_URL);

			if( !$response ){
				return false;
			}
			$result = $this->xml_to_data( $response );
				return $result;
			}
			/**
			* 
			* 获取支付结果通知数据
			* return array
			*/
			public function getNotifyData(){
				//获取通知的数据
				$xml = $GLOBALS['HTTP_RAW_POST_DATA'];
				$data = array();
			if( empty($xml) ){
				return false;
			}
			$data = $this->xml_to_data( $xml );
			if( !empty($data['return_code']) ){
				if( $data['return_code'] == 'FAIL' ){
					return false;
				}
			}
				return $data;
			}
			/**
			* 接收通知成功后应答输出XML数据
			* @param string $xml
			*/
			public function replyNotify(){
			$data['return_code'] = 'SUCCESS';
			$data['return_msg'] = 'OK';
			$xml = $this->data_to_xml( $data );
			echo $xml;
			die();
			}
			/**
			* 生成APP端支付参数
			* @param $prepayid 预支付id
			*/
			public function getAppPayParams( $prepayid ){

				$data['appid'] = $this->appid;

				$data['partnerid'] = $this->mch_id;

				$data['prepayid'] = $prepayid;

				$data['package'] = 'Sign=WXPay';

				$data['noncestr'] = $this->genRandomString();

				$data['timestamp'] = time();

				$data['sign'] = $this->MakeSign( $data ); 

				return $data;
			}
			/**
			* 生成签名
			* @return 签名
			*/
			public function MakeSign( $params ){
				//签名步骤一：按字典序排序数组参数
				ksort($params);

				$string = $this->ToUrlParams($params);

				//签名步骤二：在string后加入KEY

				$string = $string . "&key=".$this->key;

				//签名步骤三：MD5加密

				$string = md5($string);

				//签名步骤四：所有字符转为大写

				$result = strtoupper($string);
				
				return $result;
			}
			/**
			* 将参数拼接为url: key=value&key=value
			* @param $params
			* @return string
			*/
			public function ToUrlParams( $params ){
			$string = '';
			if( !empty($params) ){
			$array = array();
			foreach( $params as $key => $value ){
			$array[] = $key.'='.$value;
			}
			$string = implode("&",$array);
			}
			return $string;
			}
			/**
			* 输出xml字符
			* @param $params 参数名称
			* return string 返回组装的xml
			**/
			public function data_to_xml( $params ){
			if(!is_array($params)|| count($params) <= 0)
			{
			return false;
			}
			$xml = "<xml>";
			foreach ($params as $key=>$val)
			{
			if (is_numeric($val)){
			$xml.="<".$key.">".$val."</".$key.">";
			}else{
			$xml.="<".$key."><![CDATA[".$val."]]></".$key.">";
			}
			}
			$xml.="</xml>";
			return $xml; 
			}
			/**
			* 将xml转为array
			* @param string $xml
			* return array
			*/
			public function xml_to_data($xml){ 
			if(!$xml){
			return false;
			}
			//将XML转为array
			//禁止引用外部xml实体
			libxml_disable_entity_loader(true);
			$data = json_decode(json_encode(simplexml_load_string($xml, 'SimpleXMLElement', LIBXML_NOCDATA)), true); 
			return $data;
			}
			/**
			* 获取毫秒级别的时间戳
			*/
			private static function getMillisecond(){
			//获取毫秒的时间戳
			$time = explode ( " ", microtime () );
			$time = $time[1] . ($time[0] * 1000);
			$time2 = explode( ".", $time );
			$time = $time2[0];
			return $time;
			}
			/**
			* 产生一个指定长度的随机字符串,并返回给用户 
			* @param type $len 产生字符串的长度
			* @return string 随机字符串
			*/
			private function genRandomString($len = 32) {
			$chars = array(
			"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k",
			"l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v",
			"w", "x", "y", "z", "A", "B", "C", "D", "E", "F", "G",
			"H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R",
			"S", "T", "U", "V", "W", "X", "Y", "Z", "0", "1", "2",
			"3", "4", "5", "6", "7", "8", "9"
			);
			$charsLen = count($chars) - 1;
			// 将数组打乱 
			shuffle($chars);
			$output = "";
			for ($i = 0; $i < $len; $i++) {
			$output .= $chars[mt_rand(0, $charsLen)];
			}
			return $output;
			}
			/**
			* 以post方式提交xml到对应的接口url
			* 
			* @param string $xml 需要post的xml数据
			* @param string $url url
			* @param bool $useCert 是否需要证书，默认不需要
			* @param int $second url执行超时时间，默认30s
			* @throws WxPayException
			*/
			private function postXmlCurl($xml, $url, $useCert = false, $second = 30){ 
			$ch = curl_init();
			//设置超时
			curl_setopt($ch, CURLOPT_TIMEOUT, $second);
			curl_setopt($ch,CURLOPT_URL, $url);
			curl_setopt($ch,CURLOPT_SSL_VERIFYPEER,FALSE);

			curl_setopt($ch,CURLOPT_SSL_VERIFYHOST,2);
			//设置header
			curl_setopt($ch, CURLOPT_HEADER, FALSE);
			//要求结果为字符串且输出到屏幕上
			curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
			if($useCert == true){
			//设置证书
			//使用证书：cert 与 key 分别属于两个.pem文件
			curl_setopt($ch,CURLOPT_SSLCERTTYPE,'PEM');
			//curl_setopt($ch,CURLOPT_SSLCERT, WxPayConfig::SSLCERT_PATH);
			curl_setopt($ch,CURLOPT_SSLKEYTYPE,'PEM');
			//curl_setopt($ch,CURLOPT_SSLKEY, WxPayConfig::SSLKEY_PATH);
			}
			//post提交方式
			curl_setopt($ch, CURLOPT_POST, TRUE);
			curl_setopt($ch, CURLOPT_POSTFIELDS, $xml);
			//运行curl
			$data = curl_exec($ch);
			//返回结果
			if($data){
			curl_close($ch);
			return $data;
			} else { 
			$error = curl_errno($ch);
			curl_close($ch);
			return false;
			}
			}
			/**
			* 错误代码
			* @param $code 服务器输出的错误代码
			* return string
			*/
					public function error_code( $code ){
							$errList = array(
							'NOAUTH' => '商户未开通此接口权限',
							'NOTENOUGH' => '用户帐号余额不足',
							'ORDERNOTEXIST' => '订单号不存在',
							'ORDERPAID' => '商户订单已支付，无需重复操作',
							'ORDERCLOSED' => '当前订单已关闭，无法支付',
							'SYSTEMERROR' => '系统错误!系统超时',
							'APPID_NOT_EXIST' => '参数中缺少APPID',
							'MCHID_NOT_EXIST' => '参数中缺少MCHID',
							'APPID_MCHID_NOT_MATCH' => 'appid和mch_id不匹配',
							'LACK_PARAMS' => '缺少必要的请求参数',
							'OUT_TRADE_NO_USED' => '同一笔交易不能多次提交',
							'SIGNERROR' => '参数签名结果不正确',
							'XML_FORMAT_ERROR' => 'XML格式错误',
							'REQUIRE_POST_METHOD' => '未使用post传递参数 ',
							'POST_DATA_EMPTY' => 'post数据不能为空',
							'NOT_UTF8' => '未使用指定编码格式',
							); 
					if( array_key_exists( $code , $errList ) ){
						return $errList[$code];
					}
				}
}